Binding post terminal



Nov. 6, 1934.

S. S. STOLP BINDING POST TERMINAL Original Filed June 11, 1928 Elia-SAMUEL S. STOLP. INVENTOR.

A TTORNEY.

Patented Nov. 6, 1934 1,979,582 lBINDING Pos'r TERMINAL Samuel. S.Stolp, Louisville, Ky., assignor to Cheatharn Electric Switching DeviceCom- Original application June 11," 1928, Serial No. 284,636. Dividedand this application January 20, 1930, Serial No. 422,124

5 Claims. (01. 173-259) This application is a divisionoi my copendingapplication Serial No.284,636, filed Junell. 1928, Patent 1,824,844issued September 29, 1931.

This invention relates to improvements in binding post terminals forattaching electric wires to devices and has for its principal object toprovide an article of this character for quickly, easily and effectivelysupporting the A wire in a predetermined position.

U The object of my invention is to produce an improved terminal forsecuring electriealconductors in'the form of wires'to any kind ofapparatus, in which not only a good mechanical and electrical connectionis obtained, but a 3 highly desirable definite locking of the conductorsecuring means is accomplished without employing an auxiliary lockingpart, such as a lock nut, set screw, lock washer, et cetera'.

An outstanding feature in the accomplishment 5/ or" thislocking action,is the embodiment of the principle in a simple convenient terminal whichcan be actuated without the employment of special tools, or having toresort to special instructions. In fact the locking is automaticallyaccomplished without thought on the part of the user.

Figure l is illustrative of the terminal attached to apparatus shownprincipally in crosssection.

" Fig. 2 is a cross-sectional elevation of the fixed or shell membershownin crosssectional elevation with the terminal screw removed.

Fig. 3 is a top view of Fig. 2,

Referring now to the drawing in detail, the invention comprises aterminal construction fa oned in the head of a clamping bolt. Refor mgin particular to Figure 1, it will be noted that the clamping bolt isillus' rated as having an annular head 21, with a shank 19-extendingthrough an insulating bar 20, however, it will be apparent that the bar20 may be of metal without changing the spirit of the invention. In theouter face of the annular head 21, a concen tric annular recess isformed. This recess may be fashioned by counterboring, die casting, ormany other well known processes familiar to those skilled in the artof'working metals. The bottom of the recess, as illustrated in eitherFigures 1 or 2, is fiat and has the surrounding walls of the recesssubstantially perpendicular to its bottom surface. Centrally disposed inthe bottom of the recess 22, is an internally threaded opening 19a whichextends into the shank 19 of the clamping bolt. It will be noted thatthe upper portion of the internally threaded opening 19a is drilledslightly larger, thereby removing the threads adjacent the bottom oi therecess, the object of which will be described later. A terminal screw23, comprising a cylindrical shaped bolt head having a substantiallyflat under surface and an externally threaded shank for engaging theinternally threaded opening, is employed to secure an electricalconductor 25 to the clamping bolt. Attention is directed to theconstruction of the cylindrical head of the terminal screw 23, which ismade substantially the same diameter as the recess 22, such thatnormally the cylindrical head will be receivable in the recess Withoutbinding on the walls 21a and 221). In order to insure that the head ofthe terminal screw 23 will not bind on the walls of the recess beforethe Wire connection is properly clamped, the internalscrew threads 1.9aare arranged to engage the threaded portion of the terminal screwloosely. Referring a to Figs. 2 and 3, it will be noted that the outerface of the annular clamping bolt head 21 is cross milled, providingcit-centered linearly disposed slots 24, 24. It will be further notedthat the outer ends of these slots terminate on the 2:,

outside surface of the clamping bolt head while the inner ends terminatewithin the recess 22. This cross milling divides the wall of the recessinto major and minor arcuate segments 22b and 210. respectively,providing openings by which a wire conductor 25 may be extended throughthe recess between the threadedshank of the terminal screw, and arcuatesegment 21a.

The off-centered disposition of these slots there fore serves to holdthe conductor in a definite location within the recess, such that theconductor will be held out of engagement with the threaded portion ofthe terminal screw and in a preferred position where it may be securedby the flat under surface of the terminal screw head. This feature is ofgreat importance, especially when stranded conductors are employed,since it definitely prevents any strand of a conductor becomingentangled in the threads of the terminal screw, as is the case in manyordinary forms of terminal constructions. The off-com tered dispositionof the slots 24, 24 also serves to introduce a frictional lockingfeature for the terminal screw head. This feature is accom plished whenthe terminal screw engages the conductor 25, at which time the conductorbecomes a fulcrum, resulting in the head of the terminal screw engagingthe major arcuate segment'22b diametrically opposite the point where theterminal connection is being made. It is therefore apparent, that theoff-centered slots provide a further desirable feature inasmuch as thesegment 22b, which supports the head of the terminal screw 23 to providethe frictional lock, is formed of the larger portion, while the segment21a which serves only to hold the conductor within the head of theterminal screw is formed of the smaller portion. When small conductors,were secured by the terminal screw thread portion 190, loose asmentioned hereto fore. Another important feature of having thesupporting segment 22?) partially surrounding the terminal screw head,is that a supporting surface for the head of the terminal screw isprovided even though the wire is clamped at any point along the clampingsurface.

It will be noted that under normal conditions, whileclamping wire 25under the head of screw 23 that, as pressure is applied and increased,there will be a definite tendency toward a tilting action of the screw.This tilting action will move the head into engagement with the supporting side wall 22b, thereby effecting a definite braking action,which will directly and automatically produce an effective lock againstvibration. l/Vere it not for the fact that the side wall 222) is engagedat the time the tilting action begins, to support the screw head andproduce the desired locking action, the shank of the screw would be bentto such an extent that removal of the screw would be made difficult.

Special attention is directed to the fact that this terminal,althoughdefinitely locked, is always ready to be operated as an ordinary screwterminal without the use of any special or auxiliary equipment andwithout in any way marring any of the parts, while being operated ineither direction, which is incident to the use of many ordinary lockingdevices.

While this terminal is shown as having been especially fashioned frommaterial to form a separate terminal unit, it may readily beincorporated into other forms without departing from the spirit of thisinvention, therefore, I wish to be limited only by the appended claims.

I claim:

1. A terminal connection comprising a clamping bolt having a shank andan annular head, a cylindrical recess formed in the outer face of thesaid annular head having its bottom perpendicular to the walls of saidrecess, a centrally disposed internally threaded opening in the bottomof said recess extending into the shank of the said clamping bolt, aconductor securing means fashioned with a cylindrical screw head havinga fiat under surface perpendicular to the periphery of said screw head,and a centrally disposed externally threaded shank extending from thesaid under surface for engaging the said internally threaded opening,said recess adapted to closely fit the periphery of said cylindricalscrew head, and off-centered linearly disposed conductor receiving slotsin the outer face of the said annular head, having their outer endsterminating on the periphery of the said annular head and their innerends terminating within the said recess.

2. An electrical connector for lead wires comprising a binding postprovided at one end with securing means, and fashioned with acylindrical recess having a flat bottom perpendicular to the walls ofsaidrecess in the other end forming a flange in prolongation of the saidpost except as interrupted by a pair of linearly disposed slotsintersecting the said flange on one side of the diameter of the saidrecess, the bottom of said slots adapted to register with the bottom ofsaid recess, a centrally disposed threaded opening in the bottom of thesaid recess, a terminal screw inserted in the said threaded openingfashioned with a cylindrical screw head concentric with the threadedportion of said screw and having a flat under surface perpendicular tothe periphery of the said screw head, said screw head adapted to closelyfit said recess and to secure a straight wire extending through saidslots into said recess betweenthe flat bottom of the said recess and theflat under surface of the head of said terminal screw.

3. A binding post terminal comprising an annular base provided with ashank for securing the same, the said base having a central threadedopening, a terminal screw inserted in the said threaded openingfashioned with a concentric cylindrical head, upstanding supportingmembers formed on said base providing a channel to receive a wire, theinner surfaces of the said members forming a cylindrical recess closelyfitting the periphery of the said terminal screw head, the outersurfaces of the members forming extensions of the periphery of the saidbase.

4. A terminal construction comprising an attaching base having athreaded opening, a terminal screw inserted in the said threaded openingfashioned with a concentric cylindrical head, upstanding supportingmembers formed on said base providing a channel to receive a wire, theinner surfaces of the said members forming a cylindrical recessconcentric with the said threaded opening and closely fitting theperiphery of the said terminal screw head.

5. A terminal construction comprising an attaching base having athreaded opening, a terminal screw inserted in the said threaded portionfashioned with a concentric cylindrical head, a pair of upstandingsupporting members formed on the said base, the inner surfaces of thesaid members forming a cylindrical recess concentric with the saidthreaded opening and closely fitting the periphery of the said terminalscrew head, said members adapted to provide a channel to guide andretain a wire extending through the said recess out of mechanicalengagement with the said threaded portion of the terminal screw.

SAMUEL S. STOLP.

